A uniform sphere of weight $W$ and radius $3\,m$ is being held by a string of length $2\,m$ , attached to a frictionless wall as shown in the figure. The tension in the string will be

Define $SI$ unit of force $N$. Define $CGS$ unit of force dyne.

Two blocks of mass $2 \,kg$ and $4 kg$ are accelerated with same acceleration by a force $10 \,N$ as shown in figure on a smooth horizontal surface. Then the spring force between the two blocks will be .......... $N$ (spring is massless)

A uniform thick string of length $5\,m$ is resting on a horizontal frictionless surface. It is pulled by a horizontal force of $5\,N$ from one end. The tension in the string at $1\,m$ from the force applied is ......... $N$

Two masses $m$ and $M$ are attached to the strings as shown in the figure. If the system is in equilibrium, then 

An object of mass $5\, kg$ is thrown vertically upwards from the ground. The air resistance produces a constant retarding force of $10\, N$ throughout the motion. The ratio of time of ascent to the time of descent will be equal to $\left[\right.$Use $g =10 \,ms ^{-2}]$